backends/hostmem.c

   1 /*
   2  * QEMU Host Memory Backend
   3  *
   4  * Copyright (C) 2013-2014 Red Hat Inc
   5  *
   6  * Authors:
   7  *   Igor Mammedov <imammedo@redhat.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  */
  12
  13 #include "qemu/osdep.h"
  14 #include "sysemu/hostmem.h"
  15 #include "hw/boards.h"
  16 #include "qapi/error.h"
  17 #include "qapi/qapi-builtin-visit.h"
  18 #include "qapi/visitor.h"
  19 #include "qemu/config-file.h"
  20 #include "qom/object_interfaces.h"
  21 #include "qemu/mmap-alloc.h"
  22 #include "qemu/madvise.h"
  23
  24 #ifdef CONFIG_NUMA
  25 #include <numaif.h>
  26 #include <numa.h>
  27 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_DEFAULT != MPOL_DEFAULT);
  28 /*
  29  * HOST_MEM_POLICY_PREFERRED may either translate to MPOL_PREFERRED or
  30  * MPOL_PREFERRED_MANY, see comments further below.
  31  */
  32 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_PREFERRED != MPOL_PREFERRED);
  33 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_BIND != MPOL_BIND);
  34 QEMU_BUILD_BUG_ON(HOST_MEM_POLICY_INTERLEAVE != MPOL_INTERLEAVE);
  35 #endif
  36
  37 char *
  38 host_memory_backend_get_name(HostMemoryBackend *backend)
  39 {
  40     if (!backend->use_canonical_path) {
  41         return g_strdup(object_get_canonical_path_component(OBJECT(backend)));
  42     }
  43
  44     return object_get_canonical_path(OBJECT(backend));
  45 }
  46
  47 static void
  48 host_memory_backend_get_size(Object *obj, Visitor *v, const char *name,
  49                              void *opaque, Error **errp)
  50 {
  51     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
  52     uint64_t value = backend->size;
  53
  54     visit_type_size(v, name, &value, errp);
  55 }
  56
  57 static void
  58 host_memory_backend_set_size(Object *obj, Visitor *v, const char *name,
  59                              void *opaque, Error **errp)
  60 {
  61     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
  62     uint64_t value;
  63
  64     if (host_memory_backend_mr_inited(backend)) {
  65         error_setg(errp, "cannot change property %s of %s ", name,
  66                    object_get_typename(obj));
  67         return;
  68     }
  69
  70     if (!visit_type_size(v, name, &value, errp)) {
  71         return;
  72     }
  73     if (!value) {
  74         error_setg(errp,
  75                    "property '%s' of %s doesn't take value '%" PRIu64 "'",
  76                    name, object_get_typename(obj), value);
  77         return;
  78     }
  79     backend->size = value;
  80 }
  81
  82 static void
  83 host_memory_backend_get_host_nodes(Object *obj, Visitor *v, const char *name,
  84                                    void *opaque, Error **errp)
  85 {
  86     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
  87     uint16List *host_nodes = NULL;
  88     uint16List **tail = &host_nodes;
  89     unsigned long value;
  90
  91     value = find_first_bit(backend->host_nodes, MAX_NODES);
  92     if (value == MAX_NODES) {
  93         goto ret;
  94     }
  95
  96     QAPI_LIST_APPEND(tail, value);
  97
  98     do {
  99         value = find_next_bit(backend->host_nodes, MAX_NODES, value + 1);
 100         if (value == MAX_NODES) {
 101             break;
 102         }
 103
 104         QAPI_LIST_APPEND(tail, value);
 105     } while (true);
 106
 107 ret:
 108     visit_type_uint16List(v, name, &host_nodes, errp);
 109     qapi_free_uint16List(host_nodes);
 110 }
 111
 112 static void
 113 host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name,
 114                                    void *opaque, Error **errp)
 115 {
 116 #ifdef CONFIG_NUMA
 117     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 118     uint16List *l, *host_nodes = NULL;
 119
 120     visit_type_uint16List(v, name, &host_nodes, errp);
 121
 122     for (l = host_nodes; l; l = l->next) {
 123         if (l->value >= MAX_NODES) {
 124             error_setg(errp, "Invalid host-nodes value: %d", l->value);
 125             goto out;
 126         }
 127     }
 128
 129     for (l = host_nodes; l; l = l->next) {
 130         bitmap_set(backend->host_nodes, l->value, 1);
 131     }
 132
 133 out:
 134     qapi_free_uint16List(host_nodes);
 135 #else
 136     error_setg(errp, "NUMA node binding are not supported by this QEMU");
 137 #endif
 138 }
 139
 140 static int
 141 host_memory_backend_get_policy(Object *obj, Error **errp G_GNUC_UNUSED)
 142 {
 143     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 144     return backend->policy;
 145 }
 146
 147 static void
 148 host_memory_backend_set_policy(Object *obj, int policy, Error **errp)
 149 {
 150     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 151     backend->policy = policy;
 152
 153 #ifndef CONFIG_NUMA
 154     if (policy != HOST_MEM_POLICY_DEFAULT) {
 155         error_setg(errp, "NUMA policies are not supported by this QEMU");
 156     }
 157 #endif
 158 }
 159
 160 static bool host_memory_backend_get_merge(Object *obj, Error **errp)
 161 {
 162     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 163
 164     return backend->merge;
 165 }
 166
 167 static void host_memory_backend_set_merge(Object *obj, bool value, Error **errp)
 168 {
 169     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 170
 171     if (!host_memory_backend_mr_inited(backend)) {
 172         backend->merge = value;
 173         return;
 174     }
 175
 176     if (value != backend->merge) {
 177         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 178         uint64_t sz = memory_region_size(&backend->mr);
 179
 180         qemu_madvise(ptr, sz,
 181                      value ? QEMU_MADV_MERGEABLE : QEMU_MADV_UNMERGEABLE);
 182         backend->merge = value;
 183     }
 184 }
 185
 186 static bool host_memory_backend_get_dump(Object *obj, Error **errp)
 187 {
 188     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 189
 190     return backend->dump;
 191 }
 192
 193 static void host_memory_backend_set_dump(Object *obj, bool value, Error **errp)
 194 {
 195     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 196
 197     if (!host_memory_backend_mr_inited(backend)) {
 198         backend->dump = value;
 199         return;
 200     }
 201
 202     if (value != backend->dump) {
 203         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 204         uint64_t sz = memory_region_size(&backend->mr);
 205
 206         qemu_madvise(ptr, sz,
 207                      value ? QEMU_MADV_DODUMP : QEMU_MADV_DONTDUMP);
 208         backend->dump = value;
 209     }
 210 }
 211
 212 static bool host_memory_backend_get_prealloc(Object *obj, Error **errp)
 213 {
 214     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 215
 216     return backend->prealloc;
 217 }
 218
 219 static void host_memory_backend_set_prealloc(Object *obj, bool value,
 220                                              Error **errp)
 221 {
 222     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 223
 224     if (!backend->reserve && value) {
 225         error_setg(errp, "'prealloc=on' and 'reserve=off' are incompatible");
 226         return;
 227     }
 228
 229     if (!host_memory_backend_mr_inited(backend)) {
 230         backend->prealloc = value;
 231         return;
 232     }
 233
 234     if (value && !backend->prealloc) {
 235         int fd = memory_region_get_fd(&backend->mr);
 236         void *ptr = memory_region_get_ram_ptr(&backend->mr);
 237         uint64_t sz = memory_region_size(&backend->mr);
 238
 239         if (!qemu_prealloc_mem(fd, ptr, sz, backend->prealloc_threads,
 240                                backend->prealloc_context, errp)) {
 241             return;
 242         }
 243         backend->prealloc = true;
 244     }
 245 }
 246
 247 static void host_memory_backend_get_prealloc_threads(Object *obj, Visitor *v,
 248     const char *name, void *opaque, Error **errp)
 249 {
 250     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 251     visit_type_uint32(v, name, &backend->prealloc_threads, errp);
 252 }
 253
 254 static void host_memory_backend_set_prealloc_threads(Object *obj, Visitor *v,
 255     const char *name, void *opaque, Error **errp)
 256 {
 257     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 258     uint32_t value;
 259
 260     if (!visit_type_uint32(v, name, &value, errp)) {
 261         return;
 262     }
 263     if (value <= 0) {
 264         error_setg(errp, "property '%s' of %s doesn't take value '%d'", name,
 265                    object_get_typename(obj), value);
 266         return;
 267     }
 268     backend->prealloc_threads = value;
 269 }
 270
 271 static void host_memory_backend_init(Object *obj)
 272 {
 273     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 274     MachineState *machine = MACHINE(qdev_get_machine());
 275
 276     /* TODO: convert access to globals to compat properties */
 277     backend->merge = machine_mem_merge(machine);
 278     backend->dump = machine_dump_guest_core(machine);
 279     backend->reserve = true;
 280     backend->prealloc_threads = machine->smp.cpus;
 281 }
 282
 283 static void host_memory_backend_post_init(Object *obj)
 284 {
 285     object_apply_compat_props(obj);
 286 }
 287
 288 bool host_memory_backend_mr_inited(HostMemoryBackend *backend)
 289 {
 290     /*
 291      * NOTE: We forbid zero-length memory backend, so here zero means
 292      * "we haven't inited the backend memory region yet".
 293      */
 294     return memory_region_size(&backend->mr) != 0;
 295 }
 296
 297 MemoryRegion *host_memory_backend_get_memory(HostMemoryBackend *backend)
 298 {
 299     return host_memory_backend_mr_inited(backend) ? &backend->mr : NULL;
 300 }
 301
 302 void host_memory_backend_set_mapped(HostMemoryBackend *backend, bool mapped)
 303 {
 304     backend->is_mapped = mapped;
 305 }
 306
 307 bool host_memory_backend_is_mapped(HostMemoryBackend *backend)
 308 {
 309     return backend->is_mapped;
 310 }
 311
 312 size_t host_memory_backend_pagesize(HostMemoryBackend *memdev)
 313 {
 314     size_t pagesize = qemu_ram_pagesize(memdev->mr.ram_block);
 315     g_assert(pagesize >= qemu_real_host_page_size());
 316     return pagesize;
 317 }
 318
 319 static void
 320 host_memory_backend_memory_complete(UserCreatable *uc, Error **errp)
 321 {
 322     HostMemoryBackend *backend = MEMORY_BACKEND(uc);
 323     HostMemoryBackendClass *bc = MEMORY_BACKEND_GET_CLASS(uc);
 324     void *ptr;
 325     uint64_t sz;
 326
 327     if (!bc->alloc) {
 328         return;
 329     }
 330     if (!bc->alloc(backend, errp)) {
 331         return;
 332     }
 333
 334     ptr = memory_region_get_ram_ptr(&backend->mr);
 335     sz = memory_region_size(&backend->mr);
 336
 337     if (backend->merge) {
 338         qemu_madvise(ptr, sz, QEMU_MADV_MERGEABLE);
 339     }
 340     if (!backend->dump) {
 341         qemu_madvise(ptr, sz, QEMU_MADV_DONTDUMP);
 342     }
 343 #ifdef CONFIG_NUMA
 344     unsigned long lastbit = find_last_bit(backend->host_nodes, MAX_NODES);
 345     /* lastbit == MAX_NODES means maxnode = 0 */
 346     unsigned long maxnode = (lastbit + 1) % (MAX_NODES + 1);
 347     /* ensure policy won't be ignored in case memory is preallocated
 348      * before mbind(). note: MPOL_MF_STRICT is ignored on hugepages so
 349      * this doesn't catch hugepage case. */
 350     unsigned flags = MPOL_MF_STRICT | MPOL_MF_MOVE;
 351     int mode = backend->policy;
 352
 353     /* check for invalid host-nodes and policies and give more verbose
 354      * error messages than mbind(). */
 355     if (maxnode && backend->policy == MPOL_DEFAULT) {
 356         error_setg(errp, "host-nodes must be empty for policy default,"
 357                    " or you should explicitly specify a policy other"
 358                    " than default");
 359         return;
 360     } else if (maxnode == 0 && backend->policy != MPOL_DEFAULT) {
 361         error_setg(errp, "host-nodes must be set for policy %s",
 362                    HostMemPolicy_str(backend->policy));
 363         return;
 364     }
 365
 366     /* We can have up to MAX_NODES nodes, but we need to pass maxnode+1
 367      * as argument to mbind() due to an old Linux bug (feature?) which
 368      * cuts off the last specified node. This means backend->host_nodes
 369      * must have MAX_NODES+1 bits available.
 370      */
 371     assert(sizeof(backend->host_nodes) >=
 372            BITS_TO_LONGS(MAX_NODES + 1) * sizeof(unsigned long));
 373     assert(maxnode <= MAX_NODES);
 374
 375 #ifdef HAVE_NUMA_HAS_PREFERRED_MANY
 376     if (mode == MPOL_PREFERRED && numa_has_preferred_many() > 0) {
 377         /*
 378          * Replace with MPOL_PREFERRED_MANY otherwise the mbind() below
 379          * silently picks the first node.
 380          */
 381         mode = MPOL_PREFERRED_MANY;
 382     }
 383 #endif
 384
 385     if (maxnode &&
 386         mbind(ptr, sz, mode, backend->host_nodes, maxnode + 1, flags)) {
 387         if (backend->policy != MPOL_DEFAULT || errno != ENOSYS) {
 388             error_setg_errno(errp, errno,
 389                              "cannot bind memory to host NUMA nodes");
 390             return;
 391         }
 392     }
 393 #endif
 394     /* Preallocate memory after the NUMA policy has been instantiated.
 395      * This is necessary to guarantee memory is allocated with
 396      * specified NUMA policy in place.
 397      */
 398     if (backend->prealloc && !qemu_prealloc_mem(memory_region_get_fd(&backend->mr),
 399                                                 ptr, sz,
 400                                                 backend->prealloc_threads,
 401                                                 backend->prealloc_context, errp)) {
 402         return;
 403     }
 404 }
 405
 406 static bool
 407 host_memory_backend_can_be_deleted(UserCreatable *uc)
 408 {
 409     if (host_memory_backend_is_mapped(MEMORY_BACKEND(uc))) {
 410         return false;
 411     } else {
 412         return true;
 413     }
 414 }
 415
 416 static bool host_memory_backend_get_share(Object *o, Error **errp)
 417 {
 418     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 419
 420     return backend->share;
 421 }
 422
 423 static void host_memory_backend_set_share(Object *o, bool value, Error **errp)
 424 {
 425     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 426
 427     if (host_memory_backend_mr_inited(backend)) {
 428         error_setg(errp, "cannot change property value");
 429         return;
 430     }
 431     backend->share = value;
 432 }
 433
 434 #ifdef CONFIG_LINUX
 435 static bool host_memory_backend_get_reserve(Object *o, Error **errp)
 436 {
 437     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 438
 439     return backend->reserve;
 440 }
 441
 442 static void host_memory_backend_set_reserve(Object *o, bool value, Error **errp)
 443 {
 444     HostMemoryBackend *backend = MEMORY_BACKEND(o);
 445
 446     if (host_memory_backend_mr_inited(backend)) {
 447         error_setg(errp, "cannot change property value");
 448         return;
 449     }
 450     if (backend->prealloc && !value) {
 451         error_setg(errp, "'prealloc=on' and 'reserve=off' are incompatible");
 452         return;
 453     }
 454     backend->reserve = value;
 455 }
 456 #endif /* CONFIG_LINUX */
 457
 458 static bool
 459 host_memory_backend_get_use_canonical_path(Object *obj, Error **errp)
 460 {
 461     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 462
 463     return backend->use_canonical_path;
 464 }
 465
 466 static void
 467 host_memory_backend_set_use_canonical_path(Object *obj, bool value,
 468                                            Error **errp)
 469 {
 470     HostMemoryBackend *backend = MEMORY_BACKEND(obj);
 471
 472     backend->use_canonical_path = value;
 473 }
 474
 475 static void
 476 host_memory_backend_class_init(ObjectClass *oc, void *data)
 477 {
 478     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
 479
 480     ucc->complete = host_memory_backend_memory_complete;
 481     ucc->can_be_deleted = host_memory_backend_can_be_deleted;
 482
 483     object_class_property_add_bool(oc, "merge",
 484         host_memory_backend_get_merge,
 485         host_memory_backend_set_merge);
 486     object_class_property_set_description(oc, "merge",
 487         "Mark memory as mergeable");
 488     object_class_property_add_bool(oc, "dump",
 489         host_memory_backend_get_dump,
 490         host_memory_backend_set_dump);
 491     object_class_property_set_description(oc, "dump",
 492         "Set to 'off' to exclude from core dump");
 493     object_class_property_add_bool(oc, "prealloc",
 494         host_memory_backend_get_prealloc,
 495         host_memory_backend_set_prealloc);
 496     object_class_property_set_description(oc, "prealloc",
 497         "Preallocate memory");
 498     object_class_property_add(oc, "prealloc-threads", "int",
 499         host_memory_backend_get_prealloc_threads,
 500         host_memory_backend_set_prealloc_threads,
 501         NULL, NULL);
 502     object_class_property_set_description(oc, "prealloc-threads",
 503         "Number of CPU threads to use for prealloc");
 504     object_class_property_add_link(oc, "prealloc-context",
 505         TYPE_THREAD_CONTEXT, offsetof(HostMemoryBackend, prealloc_context),
 506         object_property_allow_set_link, OBJ_PROP_LINK_STRONG);
 507     object_class_property_set_description(oc, "prealloc-context",
 508         "Context to use for creating CPU threads for preallocation");
 509     object_class_property_add(oc, "size", "int",
 510         host_memory_backend_get_size,
 511         host_memory_backend_set_size,
 512         NULL, NULL);
 513     object_class_property_set_description(oc, "size",
 514         "Size of the memory region (ex: 500M)");
 515     object_class_property_add(oc, "host-nodes", "int",
 516         host_memory_backend_get_host_nodes,
 517         host_memory_backend_set_host_nodes,
 518         NULL, NULL);
 519     object_class_property_set_description(oc, "host-nodes",
 520         "Binds memory to the list of NUMA host nodes");
 521     object_class_property_add_enum(oc, "policy", "HostMemPolicy",
 522         &HostMemPolicy_lookup,
 523         host_memory_backend_get_policy,
 524         host_memory_backend_set_policy);
 525     object_class_property_set_description(oc, "policy",
 526         "Set the NUMA policy");
 527     object_class_property_add_bool(oc, "share",
 528         host_memory_backend_get_share, host_memory_backend_set_share);
 529     object_class_property_set_description(oc, "share",
 530         "Mark the memory as private to QEMU or shared");
 531 #ifdef CONFIG_LINUX
 532     object_class_property_add_bool(oc, "reserve",
 533         host_memory_backend_get_reserve, host_memory_backend_set_reserve);
 534     object_class_property_set_description(oc, "reserve",
 535         "Reserve swap space (or huge pages) if applicable");
 536 #endif /* CONFIG_LINUX */
 537     /*
 538      * Do not delete/rename option. This option must be considered stable
 539      * (as if it didn't have the 'x-' prefix including deprecation period) as
 540      * long as 4.0 and older machine types exists.
 541      * Option will be used by upper layers to override (disable) canonical path
 542      * for ramblock-id set by compat properties on old machine types ( <= 4.0),
 543      * to keep migration working when backend is used for main RAM with
 544      * -machine memory-backend= option (main RAM historically used prefix-less
 545      * ramblock-id).
 546      */
 547     object_class_property_add_bool(oc, "x-use-canonical-path-for-ramblock-id",
 548         host_memory_backend_get_use_canonical_path,
 549         host_memory_backend_set_use_canonical_path);
 550 }
 551
 552 static const TypeInfo host_memory_backend_info = {
 553     .name = TYPE_MEMORY_BACKEND,
 554     .parent = TYPE_OBJECT,
 555     .abstract = true,
 556     .class_size = sizeof(HostMemoryBackendClass),
 557     .class_init = host_memory_backend_class_init,
 558     .instance_size = sizeof(HostMemoryBackend),
 559     .instance_init = host_memory_backend_init,
 560     .instance_post_init = host_memory_backend_post_init,
 561     .interfaces = (InterfaceInfo[]) {
 562         { TYPE_USER_CREATABLE },
 563         { }
 564     }
 565 };
 566
 567 static void register_types(void)
 568 {
 569     type_register_static(&host_memory_backend_info);
 570 }
 571
 572 type_init(register_types);